COLUMBUS, Ohio - Soybean diseases, such as Phytophthora root rot and Sclerotinia white mold, are the biggest limiting factors when it comes to producing a good crop.
"Diseases reduce yields at least 6-10 percent every year," said Ohio State University agronomist Jim Beuerlein. "When selecting soybean varieties, farmers should first look for those that show a resistance or tolerance to diseases."
Resistance to diseases was just one characteristic Ohio State University researchers focused on when testing varieties for the 2001 Ohio Soybean Performance Trials. Researchers evaluated 190 varieties at five test sites throughout the state and analyzed such characteristics as plant height, lodging potential, seed size, maturity, protein and oil percentage, and yield potential. The report is available at all county offices of Ohio State University Extension or by logging on to http://www.ag.ohio-state.edu/~perf.
Beuerlein said the soybean varieties tested well throughout the state, with yields averaging between 54-68 bushels per acre for normal and Roundup Ready early and late maturing soybeans.
"In some locations diseases were a factor, but overall we had a good growing season," said Beuerlein. "We had good weed control and the soil fertility was excellent."
When farmers select varieties for next season, they should take into account such factors as weather and soil conditions for the region they live in, said Beuerlein. "A variety may be the best for one location, but not the best for another," he said. "The Northwest region, for example, is more ideal for root rot development than other parts of Ohio because of the clay soils. They just don't drain well." The organism that causes root rot thrives in poorly drained soils.
The following are some tips researchers recommend when selecting soybean varieties:
* Choose a range of maturities to spread out the harvest season. Early varieties in narrow rows perform as well as late varieties.
* Varieties should have low lodging scores of one or two. Reducing the seeding rate of lodging-susceptible varieties will reduce lodging without affecting yield.
* Select varieties with a Phytophthora partial resistance score of less than five to reduce the loss of yield to root rot.
* Selecting varieties with one or more Phytophthora resistance genes (Rps1b, Rps1c, Rps1k, or Rps3a) will also help reduce yield loss.
* Varieties with a Sclerotinia rating of "M" will have much less yield loss to Sclerotinia white mold than varieties without the "M" rating if conditions are favorable for that disease.
* All seed should be treated with fungicides to improve plant stand and root system health, regardless of variety, crop rotation, tillage, planting date, or seeding rate.
The purpose of the Ohio Soybean Performance Trials is to give soybean growers comparative information for selecting the best varieties for their unique production systems.
"By using this data, every farmer in Ohio is capable of picking up an additional bushel in yield. If every farmer got just one more bushel per acre, the value would have been about $22 million from the 4.5 million acres produced in 2001," said Beuerlein. " And farmers can easily pick up an additional bushel by doing a good job of variety selection."